What is embedded system?Electrical control system which is designed to perform predefined specific function with combination of computer hardware and software. RISC processorAcronym for Reduced Instruction Set Computer. A microprocessor that carries out fewer instructions than traditional microprocessors so that it can work more quickly. What is kernel?kernel is an bridge between OS and Hardware. kernel is the heart the of OS( Operating System ), usually kernel only operate both the hardware and software, the operating system is nothing but wrapper of the kernel, through os user can achieve his operation easily ( user friendly ). OS is defines as interface between user and computer. RTOSAn operating system designed specifically for use in real-time systems that should respond to external events within a short and predictable time frame. Define Re-entrence functionA function is concurrently accessed by more than one task is called re-entrance function. Both task have won stack of the re-entrance function. Types of Tasks
User Space Task Thread SafeShared data are protected by the semaphore is called safe thread. CPUThe Central Processing Unit (CPU), It contains instruction processing logic, instruction and data pointers, and an operand register. It directly accesses the high speed on-chip memory, which can store data or programs. Where larger amounts of memory are required, the processor can access memory via the External Memory Interface (EMI). Does *p++ increment p, or what it points to?Unary operators like *, ++, and -- all associate (group) from right to left. Therefore, *p++ increments p (and returns the value pointed to by p before the increment). To increment the value pointed to by p, use (*p)++ (or perhaps ++*p, if the order of the side effect doesn't matter). Cross CompilerA compiler may run on one machine( Host ) and produce object code for another machine( Target ) is called cross compiler. LoaderLoder is a program which loads another executable code into main memory from secondary device and makes the CPU to run the loaded code. Register Storage Class
register is used to define local variables that should be stored in a register instead of RAM. This means that the variable has a maximum size equal to the register size (usually one word) and cant have the unary '&' operator applied to it (as it does not have a memory location).
How to find give no is 2 power of n
f=( ( no & ( no-1 ) ) == 0 ) Types of Random Access Memory ( RAM )
It is called as Read/Write Memory, it requires external power to maintain memory content. Types of Read Only Memory (ROM)
Contains non-volatile content and without the need for an external power source. Flash MemoryThe flash memory is a variation of EEPROM, which allows for block-level (e.g., 512-byte) programmability that is much faster than EEPROM. EMI
EMI means External Memory Interface. This is used to communicate with external memory. What is static function?In the case of static function, the function is local to that file only. We cant access the static function from another file. What is preemptive scheduler?A scheduler that may switch between threads at any time. CompilerCompiler is a program which converts the source code into mechine code( object files ). It compiles the source program as a whole. InterpreterInterpreter is a program which converts the source code into mechine code( executable files ). It compiles & executes the source program line by line. LinkerLinker is a program which is used to combine one or more object files & creates executable files( machine code ). TunerAn electronic receiver that detects and demodulates and amplifies transmitted signals. Volatile Pointer
Volatile is a variable which may change the value without knowing of code.
A variable should be declared volatile whenever its value could change unexpectedly.
In practice, only three types of variables could change: Static Keyword and Variable
* Static keyword is used to declare a global variable. static int a = 10; main() { } function1() { } . . function..n() { } we can access the static variable 'a' through the entire program. If we declare, main() { static int a = 10; .... } function1( args ) { static int b = 10; ... }* The static variable 'a' can access only in main function.But that value is persistent until the program end. * The static variable 'b' can access only in function1. But the value of 'b' is persistent until the program end. * Function main can't access the variable 'b'. such that function1 can't access the variable 'a'. |